Does cruise control disable overdrive?

[oakback]

I've noticed this many times on long car trips. I'll have CC off, maintaining a set speed on long, flat, straight sections of highway, then turn CC on for the exact same speed (verified on GPS), and it'll downshift and hold 3rd. I'll turn CC off, and it'll upshift to 4th and hold it just fine.

What about CC causes that to happen?

 

[MountaineerLC]

No, CC doesn’t disable OD. However, I find the CC on my ‘01 to be very aggressive and quickly downshifts to maintain the set speed, even on minor inclines.

There have been a few times I’ve seen the CC downshift to 2nd gear then upshift to 3rd when loaded and pulling steep inclines at 60mph.